PHOTO DETECTING APPARATUS

摘要

A photo detecting apparatus (1) comprises a photo diode (PD<SUB>m,n</SUB>), a switch (SW<SUB>m,n</SUB>), an integrating circuit (12<SUB>m</SUB>) and a CDS circuit (13<SUB>m</SUB>). The integrating circuit (12<SUB>m</SUB>) accumulates a charge, which is received from the photo diode (PD<SUB>m,n</SUB>) via the switch (SW<SUB>m,n</SUB>) and a wiring (L<SUB>m</SUB>), into a capacitor (C<SUB>f</SUB>) and outputs a voltage in accordance with the amount of the accumulated charge. The CDS circuit (13<SUB>m</SUB>) uses, as a reference voltage, a voltage outputted from the integrating circuit (12<SUB>m</SUB>) at a reference time point, at which a clamp switch (SW<SUB>3</SUB>) is opened, and outputs a voltage in accordance with the difference between a voltage outputted from the integrating circuit (12<SUB>m</SUB>) after the reference time point and the reference voltage. When the capacitance value of the wiring (L<SUB>m</SUB>) and that of the capacitor (C<SUB>f</SUB>) are represented by C<SUB>w</SUB> and C<SUB>f</SUB>, respectively, and further when the gain band product of an amplifier (A<SUB>2</SUB>) included in the integrating circuit (12<SUB>m</SUB>) is represented by GBW, a time period (T) from a time point, at which a switch (SW<SUB>2</SUB>) is opened and the integrating circuit (12<SUB>m</SUB>) becomes able to accumulate the charge, till the reference time point is equal to or greater than a predetermined value.